1. Field of the Invention
The present invention relates generally to a paper sheet counting machine, and more particularly to a safety device which is assembled with the sound-proof cover of the paper sheet counting machine.
2. Prior Art
The paper sheet counting machines disclosed in our co-pending patent applications Ser. Nos. 931,903, now U.S. Pat. No. 4,277,119 and 31,129, now U.S. Pat. No. 4,239,204, are provided with sound-proof covers operable to open or close the paper sheet counting sections in which paper sheets are held by a paper holder to be counted by means of rotary suction cylinders. These conventional paper sheet counting machines have sound-proof covers which can be closed to cover the paper sheet counting section during the counting operation by the counting mechanism including the holder for the bundle of paper sheets and the suction cylinders. The sound-proof covers can be opened as desired to gain access to the counting section for charging or discharging the bundle of paper sheets. After a bundle of paper sheets to be counted is put on the holder, a starting signal is generated to actuate the holder for shifting the bundle of paper sheet to the counting position and at the same time a motor for driving said sound-proof covers is actuated to close the covers. Alternatively, after the lapse of preset time interval from the time at which said starting signal for actuating the holder is generated, a delayed signal is delivered to said motor to start the closing operation of the sound-proof covers.
The paper sheet counting machine according to the preceding invention is advantageous in that the sound-proof covers are automatically closed simultaneously with or after a short interval from the commencement of the counting operation to shut out the noises and to ensure safety operation. However, this automatically operated sound-proof covers raise a problem that a hand or like part of the operator would be accidentally sandwiched in-between the covers. Although such an accident is not very dangerous to the operator, it is not preferred. In addition, the motor for driving the sound-proof covers is overloaded when an obstacle is sandwiched in-between the covers. Moreover, with the use of automatically driven sound-proof covers, the operator tends to pay his attention to the moving covers and is careless to place a bundle of paper sheet in position, leading to imprecise positioning of the bundle. As a result of such imprecise positioning, the number of paper sheets is erroneously counted.